Paint Bucket Question

[Bookdude]

I often use paint.net to alter the backgrounds of photos.  I use the paint bucket function.  (Yes, I am a super newbie - amatuer, etc).  Many times if I am trying to alter the background to a solid white with an object that is also light colored the paint bucket function colors much of the object white as well.  I understand how to adjust the tolerance and sometimes can overcome the problem.  I have tried to use a background color that is more of a contrast to a light or white object (ex. grey), but the same thing tends to happen.  I had reasoned that if the background is an obvious contrast paint bucket would only alter the contrasting color.

 

My question is what is how paint bucket tool function - how does it decide what to alter to white for example?  Is there any way to overcome this with background colors?  

 

[Pixey]

Hello @Bookdude please have a look at this description of the bucket tool, which hopefully answers your question:

 

https://www.getpaint.net/doc/latest/PaintBucket.html

 

[Bookdude]

Thanks Pixey - I tried everything mentioned on the link and it still doesn't solve the issue I am facing.

[toe_head2001]

Maybe the Paint Bucket is the wrong tool to use in this case.

You could try using TR's Alpha Cutter plugin.

[Woodsy]

I've tried doing the same thing as you but found it easier to use the Magic Wand, make a selection, then use the Paint Bucket to color the selected areas.

 

[HyReZ]

I use the eraser tool to clear away background elements near my main subject. I zoom in to the subject and set my eraser size to ~4. This is the few times I work with anti-aliasing enabled so that I get feathering at the edges as I erase around the subject. When this is done I set the erase to ~30 and get rid of the larger areas of background. Now I can add colors or even a new background to a new layer and merge them when I am satisfied. Usually, I will save to a PDN file before I merge so that I can come back at some future point and rework if needed.

[Bookdude]

Thanks for all the replies!  I will try all of these.  

[HyReZ]

Here is a video on what you are trying to achieve
https://www.youtube.com/watch?v=t_hpwGp2PEQ

 

Edited January 25, 2019 by HyReZ

[IHaveNoName]

An old photographic printing method of doing this sort of this might still have relevance here. I've used it myself for replacing the backgrounds around relatively simple shaped foreground objects but it does work.

 

The technique is to make a high contrast mask of the foreground ie. change the image to b/w and then adjust the brightness/contrast to get just pure black and white. There are several ways of using this mask but in this case, with a plain white background wanted, you simply use the Magic Wand tool to cut out the black part of the mask and merge the white remainder with the original image. The Magic Wand cuts the outline far more accurately when using a high contrast mask.

 

The problem is that the tonal make up of the original picture may not lend itself to this technique. You can lose fine detail at the edges very easily and you often need to do quite a bit of work retouching the mask itself.

 

You had just the same problem when this technique was used in photographic printing most typically adding new skies for landscapes but for isolating a regular shaped object on a plain background for pack shots etc it was effective. The advantage you have now with digital graphics is that, unlike film, alignment of the mask is not an issue and you can get pretty much a pixel perfect result with suitable subject matter.